regex

I am importing CSV records using Feeds module and Feeds Tamper. I need help figuring out a proper REGEX search and replace expression.

The first character is a numerical digit to represent the year. Example: the "3" in "3M" is a code for the year 2013 (or 2023, 2033, etc.).

The second character is a letter representing the month as follows:

A JAN
B FEB
C MAR
D APR
E MAY
F JUN
G JUL
H AUG
I (NOT USED)
J SEP
K OCT
L NOV
M DEC

So the code "3M" is actually 01-DEC-2013 (The day is always the first of the month)

I'm trying to use regular expressions to evaluate short-answer questions with the quiz module (rc10), and I keep getting error messages. The module doesn't seem to recognize things like brackets where they are standard in regex syntax. Can anyone tell me what regex expressions are accepted by the module? Is it documented anywhere?

PS, I've had a support-request posted on the issue queue for 5 days with no response at all. Kind of disappointing.